[Changes in the defensive and alimentary behavior of rabbits following multiple hashish administrations to different...

Chronic experiments on rabbits have shown that microinjections of 30, 60 and 90 micrograms of petroleum hashish extract into the ventromedial hypothalamic nuclei and into the central gray matter of the midbrain depresses the negative motivated excitation (fear, pain) induced by electric stimulation of these structures or by electric shock. Injection of hashish into the lateral hypothalamic area facilitates the appearance of the digestive positive motivated excitation. Repeated injections of the preparation during 3--15 days contributed to the development of tolerance to analgesic, behavioral and hypothermic effects of hashish. Discontinuation of the injections (90 micrograms) at the 30th experimental day did not reveal any distinct picture of the withdrawal syndrome. A suggestion is made that the brain structures investigated may participate in the development of pathological motivation to hashish.